I understand your thought process is to keep an external table with the variant information and update the schematic as needed. I suggest that this is a method which will lead to a mistake which could be costly.
I suggest another way of thinking about it. Keep the variant data in the variant manager in the design database, and query it from an external tool to find out what is in there. The automation functions are better suited to seeing what is in the variant manager and reporting that than being controlled externally. This way there is always direct correspondence between your design database (ref des, part numbers, etc) and the variant manager. Using an external source to manage this could easily result in a design modification that does not get transferred (manually, I'd guess) to the external Excel sheet and now you are not in sync.
I posted up methods of how to do this with vb.net in this thread. You may be able to adapt that to VBA.
Thank you very much. This should help me.